Transmit beamforming utilizing channel estimation matrix decomposition feedback in a wireless MIMO communication system
AssigneeMarvell International Ltd.
InventorsJungwon Lee, Rohit U. Nabar, Hui-Ling Lou
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Abstract
A method and apparatus for a communication system having a first transceiver device having a first plurality of antennas and a second transceiver device having a second plurality of antennas determines a channel estimation matrix describing a forward channel in which a signal travels from the first transceiver device to the second transceiver device. The channel estimation matrix is decomposed to derive a unitary matrix and an upper triangular matrix. A precoding matrix is developed using the upper triangular matrix, and the precoding matrix is used to control transmission of a modulated signal.
Claims31
A method of providing forward channel matrix information within a communication system, the communication system having i) a first transceiver device having a first plurality of antennas and ii) a second transceiver device having a second plurality of antennas, the method comprising:
- determining a channel estimation matrix describing a forward channel in which a signal travels from the first transceiver device to the second transceiver device;
- decomposing the channel estimation matrix to derive a unitary matrix and an upper triangular matrix at the second transceiver device;
- and
- transmitting at least a portion of the upper triangular matrix to the first transceiver device, wherein transmitting at least a portion of the upper triangular matrix further comprises transmitting diagonal and upper-diagonal matrix elements of the upper triangular matrix to the first transceiver device,
- wherein the upper triangular matrix is reconstructed from the diagonal and upper-diagonal matrix elements of the upper triangular matrix at the first transceiver device,
- wherein the upper triangular matrix is used to develop a precoding matrix, and
- wherein the precoding matrix is used to control transmission of a modulated signal via the first plurality of antennas.
An apparatus comprising:
- a controller configured to determine a description of a forward channel based on a signal from a beamformer;
- and
- a QR decomposition processor configured to decompose the description of the forward channel, wherein the decomposed description of the forward channel comprises a Q matrix and an upper triangular R matrix, and wherein the upper triangular R matrix comprises diagonal, upper-diagonal and lower-diagonal matrix elements;
- wherein the controller is configured to feed back to the beamformer, via a feedback channel resource having a bandwidth allocated to channel state information feedback, at least one of:
- (1) a precoding matrix calculated from the upper triangular R matrix, the precoding matrix to be used by the beamformer to produce a transmit gain pattern, and
- (2) the diagonal and upper-diagonal matrix elements of the upper triangular R matrix, wherein the upper triangular R matrix is reconstructed from the diagonal and upper-diagonal matrix elements of the upper triangular R matrix at the beamformer.
An apparatus comprising:
- a beamforming network coupled to a plurality of transmission antennas;
- and
- a controller configured to control the beamforming network using a precoding matrix so as to produce a transmit gain pattern having one or more high gain lobes via the plurality of transmission antennas based on the precoding matrix,
- wherein the precoding matrix is calculated from an upper triangular R matrix derived from a QR decomposition of a description of a forward channel, wherein the decomposed description of the forward channel comprises a Q matrix and the R matrix,
- wherein the controller is configured to receive diagonal and upper-diagonal matrix elements of the upper triangular R matrix from a beamformee, and
- wherein the controller is configured to reconstruct the upper triangular R matrix from the diagonal and upper-diagonal matrix elements.
A method of beamforming using forward channel matrix information within a communication system having a first transceiver device having a first plurality of antennas and a second transceiver device having a second plurality of antennas, the method comprising:
- receiving at least one of:
- (1) a precoding matrix from the second transceiver device, wherein the precoding matrix is calculated from an upper triangular matrix derived from a decomposition of a channel estimation matrix describing a forward channel in which a signal travels from the first transceiver device to the second transceiver device, wherein the decomposed description of the forward channel comprises a unitary matrix and the upper triangular matrix, the upper triangular matrix comprising diagonal, upper-diagonal and lower-diagonal matrix elements, and
- (2) at least a portion of the upper triangular matrix;
- developing a precoding matrix from the at least a portion of upper triangular matrix, if at least a portion of the upper triangular matrix is received from the second transceiver device;
- controlling transmission of a modulated signal via the first plurality of antennas using the developed precoding matrix;
- and
- controlling transmission of a modulated signal via the first plurality of antennas using the received precoding matrix, if the precoding matrix is received from the second transceiver device.
Dependencies are inferred from the claim text.